A lot of people say to get the 400x rather than the 450r because the 450r takes more maintenance. what does the 450r need that the 400ex dosent?

 

More frequent oil changes, valve adjustments, etc. Another thing about the 450 is that the engine oil and tranny oil are separate unlike the 400 where everything is integrated. The 450 is also liquid cooled where the 400 is air cooled so that is one more thing you gotta worry about.

Overall, you can't go wrong with either. A 450 in stock form is just about as reliable as a 400 in stock form. It all boils down to what type of riding you do, that is where you will make your ultimate decision.

 

Contrary to popular opinion, the 450r really doesn't require that much maintenance.
I went to a big bore cylinder 8 years ago and have yet to have a need to replace the piston/rings.
I have only needed to adjust the valves twice.